Such a system is well known in the art and is for instance-described in the not yet published European Patent Application 92870049.1 (Deloddere 2). In the latter application the interface module controls the access of the packets to the transmission means based on a priority value assigned to each of the modules. This value can be fixed or variable.
In case of fixed value the criterium for access assignment is fixed. This criterium can for instance be the location of the interface module or the type of information contained in the packet. The criterium is chosen at start up of the interface module and can not be changed during its working.
In the case of variable priority values conventional systems mostly use the number of packets waiting for transmission in the storage means, more specifically a waiting queue of the interface module, to determine the priority value. As a result thereof transmission by a module of high.sub.-- bitrate packets is favoured compared to the transmission of low-bitrate packets since the former packets more quickly fill the waiting queue than the latter ones.
Moreover in these conventional systems and when the priorities are variably assigned as described above predetermined types of packets accessing the transmission means via the same interface module cannot be favoured compared to other types, e.g. telephony packet cannot be favoured compared to data packets.